Mixed getter devices, with evaporated and not evaporated gettering material, for maintaining the vacuum in electronic tubes



July 20, 1965 P. DELLA PORTA MIXED GETTER DEVICES, WITH EVAPORATED ANDNOT EVAPORA'I'ED GETTERING MATERIAL, FOR MAINTAINING THE VACUUM INELECTRONIC TUBES Filed April 13. 1961 FIG. 2

FIG.3

United States Patent 3,195,716 ll/llXEB GETTER DEVIQES, WITHEVALIURA'EED AND N61 EVAPQRATED GET'EERING MATE- RIAL, FOR MAlNKAlP-ZEJGTEE VACUUM EN ELECTRGNEC EUEES Paolo Della Berta, Via Gallarate 2155,Milan, Italy Filed Apr. 13, 19251, Ser. No. 102,754 6 Claims. (53!.2tl-.4)

This invention relates to an improvement in getter devices formaintaining the vacuum in electronic tubes, and more particularly, ingetter devices of the mixed type having a closed form, such as circular,ring or disc like, containing a portion of evaporable, and a portion ofnonevaporable gettering material. Examples of this type of mixed getterdevice are described and illustrated in FlG- URES 9 and 10 of Italianpatent application No. 9,283 of December 29, 1960. One of the problemsof the utilisation of non-evaporable gettering material is the necessityof activating it at high temperatures. The invention of the aforesaidapplication No. 9,283 relates to the problem of maintaining thenon-evaporable getter at the necessary operating temperature after theactivation. This invention relates, on the contrary, to the problem ofactivating the non-evaporable getter. While operating temperaturesbetween room temperature and 800 C. are required for non-evaporablegetters, the temperatures required for activating these non-evaporablegetters range between 660 and 1500 C.

These last mentioned temperatures can be obtained by HE. (highfrequency) induced currents that travel on the closed loop provided bythe external periphery of getter devices of closed form, such asringlilre or disclilce. This invention, therefore, consists of animprovement to a mixed getter device of closed form with a portion ofevaporable gettering material disposed within a peripheral groove of agetter device of the already known type, and with a portion ofnon-evaporable gettering material disposed within a second circulargroove, disposed either interiorly or exteriorly concentric of the saidfirst groove and in proximity of the same. in this way, the HP.currents, used for the evaporation of the evaporable portion of thegetter, are used in the same time for activating the non-evaporableportion of the getter. The positioning of the second groove, more orless near the peripheral groove containing the evaporable portion,provides the means to accordingly control the temperature of thenonevaporable gettering material contained Within said second groove.

In the attached figures there are illustrated several embodiments of theinvention. In said drawing:

FiGURE l s rows a disc shaped getter device with an external peripheralupset portion defining an upwardly open groove containing an evaporablegettering material 1, and with a second upset portion defining adownwardly open groove, internally concentric with respect to the firstone, and containing a non-evaporable gettering material 2;

FEGURE 2 also shows a disclilre getter device similar to that of FlGURE1, wherein instead of the second groove, a circular aperture is foreseenwithin which a body of non-evaporable gettering material 2, in the formof a fiat ring, is pressed; in this manner both the upper and lower fiatsurfaces of the ring 2., as shown, of nonevaporable gettering materialare exposed;

FIGURE 3 is an annular getter device with a peripheral upwardly opengroove containing an evaporable gettering material it, and a seconddownwardly open groove, internally concentric with respect to the firstone, containing a non-evaporable gettering material 2;

FIGURES 4, S, 6 and 7 represent additional embodiments of annular getterdevices with directing ribs for the vapors of the evaporable getteringmaterial 1, directed inwardly of the ring, wherein the second groovecontaining the non-evaporable gettering material 2 is located internallyconcentric with respect to said ring, and is constituted by bending theinternal directing rib so as to form said second groove;

FIGURES 8 and 9 represent further forms of annular getters withdirecting flanges tor the vapors of the evaporable gettering material 1,directed inwardly of the ring, wherein the second groove containing thenon-evaporable gettering material 2 is located externally of the ring,and is constituted by bending the external directing flange so as toform said second groove.

Of course, the position of the second groove containing thenon-evaporable gettering material 2 will be provided in accordance withthe requirements dictated by the geometry for positioning the devicewithin the electronic tube, within the spirit and purpose of thisinvention, which lies in the utilisation of HF. currents for both theevaporation of the evaporable gettering material, and simultaneously foractivating the non-evaporable gettering material of a getter device ofthe mixed type. The spacing between the respective grooves containingthe getter materials determines the relative heating of the twomaterials, since the high frequency induced currents tend to flow alongthe outermost peripheral portions of the getter containers.

What I claim is:

1. In a mixed getter device for maintaining a vacuum in electronic tubesincluding an evaporable gettering rnaterial and non-evaporable getteringmaterial, a getter container means having a shape defining a closedperipheral path for the purpose of carrying induced high frequencyheating currents, a first upset portion on said container coextensivewith said peripheral path defining a first groove, said first groovecontaining an evaporable gcttering material, and a second upset portionon said container coextensive with said first upset portion andselectively spaced therefrom defining a second groove, said secondgroove containing a non-evaporable gettering maerial, whereby said highfrequency currents in said closed peripheral path simultaneouslyevaporate and activate, respectively, said evaporable and non-evaporablegetterin g materials.

2. The invention defined in claim 1, wherein the spacing between saidfirst and second upset portions is selected dependent upon thevaporization and activating temperatures, respectively, of saidevaporable and nonevaporable gettering materials.

3. The invention defined in claim ll, wherein said container comprises acircular disc.

4. The invention defined in claim 1, wherein s id second upset portionis perforated to provide an aperture therein and wherein saidnon-evaporable gettering material is mounted in said aperture.

5. The invention defined in claim l wherein said second upset portion isformed by further upsetting a part of said first upset portion.

6. The invention defined in claim 1, wherein said first upset portionincludes peripheral directing flanges for the vapors from saidevaporable gettering material therein,

0 0:9 4' and further wherein said second upset portion is formed FOREIGNPATENTS by upsetting one of said directing flanges. 736,475 9 /55 GreatBritain 830,319 3/60 Great Britain.

References Cited by the Examiner 1:079746 4/60 Germany UNITED STATESPATENTS 5 2,167,852 8/39 "R THERON E. CONDON, Primary Examiner.

,883 3/62 Meisen Q 20 6-0.4 ARTHUR GAUSS, Examiner.

1. IN A MIXED GETTER DEVICE FOR MAINTAINING A VACUUM IN ELECTRONIC TUBESINCLUDING AN EVAPORABLE GETTERING MATERIAL AND NON-EVAPORABLE GETTERINGMATERIAL, A GETTER CONTAINER MEANS HAVING A SHAPE DEFINING A CLOSEDPERIPHERAL PATH FOR THE PURPOSE OF CARRYING INDUCED HIGH FREQUENCYHEATING CURRENTS, A FIRST UPSET PORTION ON SAID CONTAINER COEXTENSIVEWITH SAID PERIPHERAL PATH DEFINING A FIRST GROOVE, SAID FIRST GROOVECONTAINING AN EVAPORABLE GETTERING MATERIAL, AND A SECOND UPSET PORTIONON SAID CONTAINER COEXTENSIVE WITH SAID FIRST UPSET PORTION ANDSELECTIVELY SPACED THEREFROM DEFINING A SECOND GROOVE, SAID SECONDGROOVE CONTAINING A NON-EVAPORABLE GETTERING MATERIAL, WHEREBY SAID HIGHFREQUENCY CURRENTS IN SAID CLOSED PERIPHERAL PATH SIMULTANEOUSLYEVAPORATE AND ACTIVATE, RESPECTIVELY, SAID EVAPORABLE AND NON-EVAPORABLEGETTERING MATERIALS.